In a large mine, a guided travel system for an unmanned vehicle in which the unmanned vehicle such as unmanned off-road dump trucks is guided and travels has been widely used in order to reduce painful works, decrease the production cost, and save the fuel.
The above-mentioned unmanned vehicle has a position measuring device that measures its running position using GPS (Global Positioning System) and the like. Additionally, a monitor station that monitors plural unmanned vehicles obtains, by surveying a work site or teaching, position data on a running course through which the unmanned vehicle is to run, and stores the position data. After receiving the position data of the running course from the monitor station via a radio communication and the like, the unmanned vehicle measures its current position (and its direction) using a position measuring device that the vehicle has, compares the measured current position at the time of traveling with the running course in a sequence, and is steered and controlled so as to sequentially reach each position on the running course.
Here, as a method for obtaining the position data of the running course, for example, a teaching method in which a teaching vehicle actually travels and memorizes the travel path has been widely used.
In this case, the teaching vehicle actually runs so as to pass through target points where the unmanned vehicle has to reach. Then, the position data regarding a path from a running start point to a target point or a path from the running start point through the target point to a running end point is obtained. There is another method that only the position data of the target point is obtained by teaching, and the running course is generated through the obtained position data of the target point.
Japanese Patent Application Laid-open No. 2000-137522 discloses the following related arts 1 and 2.
(Related Art 1)
As shown in FIG. 1, at a discharge site 21 in a mine, a discharging work is performed such that an unmanned vehicle 13 carries earth and sand, and discharges it. In this case, a teaching vehicle travels along a running course 27 to a target discharging position 26′ located near a survey line 20 that functions as a boundary line of the discharge site 21, whereby the position data of the running course 27 is obtained. As a result, the unmanned vehicle 13 can discharge the earth and sand outside the survey line 20 (to cliff) in the discharge site 21 after traveling along the taught running course 27.
(Related Art 2)
Since a discharge site 21 of a large scale mine or the like is wide, the number of target discharge positions 26′ in the vicinity of a survey line 20 reaches several hundreds points along the survey line 20. Thus, to obtain position data of running courses 27 for each of the large number of target discharge positions 26′ by the teaching work as mentioned in the related art 1, the number of the teaching works using teaching vehicles becomes increase, requiring much more time and man-hour to generate running courses.
And, as shown in FIG. 2, the teaching vehicle 40 is traveled along the survey line 20 in the discharge site 21, position data of plural target discharge positions 26′ in the discharge site 21 are generated based on the obtained position data of the survey line 20, and running courses 27 to reach each of the target discharge position are acquired through calculation process.
In a case where the related art 1 is employed, works at mines are performed as follows.
Specifically, for example, stripped earth and sand by a stripping work is loaded to an unmanned vehicle 13. The unmanned vehicle 13 travels, by guiding, to the target discharge position 26′ in the vicinity of the survey line 20 in the discharge site 21. At the target discharge position 26′, a carrier (body) performs a dumping operation toward a precipice, thereby falling off the earth and sand loaded on the carrier. The earth and sand, which does not fall off to the precipice and remains on the discharge site, in other words, pile 26c, is pushed out by a bulldozer or other leveling vehicles, and the discharge site 21 is leveled. A discharge work such that a dump truck 13 discharges and falls off earth and sand from a high position to a precipice is called as a high-dump work.
On the other hand, in a case where the related art 2 is employed, works at mines are performed as follows.
Specifically, in a similar way to the above-mentioned case, stripped earth and sand by a stripping work is loaded to an unmanned vehicle 13. The guided travel of the unmanned vehicle 13 is performed to the target discharge position 26′ in the discharge site 21. At the target discharge position 26′, the carrier performs the dumping operation, and the earth and sand loaded on the carrier is unloaded. As a result, the earth and sand is piled on the discharge site as a highly piled up pile 26c without falling off to the precipice. The bulldozer pushes out the highly piled up pile 26c, and the discharge site 21 is leveled. The discharge work such that a dump truck 13 discharges the earth and sand within the discharge site 21 is called as a paddock discharge work.
Recently, the unmanned dump track has become larger, and the earth and sand loaded on the carrier (body) reaches 300 ton or heavier.
According to the related art 1, since the earth and sand is discharged by the high-dump work, in most cases, almost all the earth and sand is fallen off to the precipice, and relatively little earth and sand remains in the discharge site 21. Consequently, as is often the case, leveling work by the bulldozer 16 is performed with relatively high operation efficiency.
However, according to the related art 2, since the earth and sand is discharged by the paddock discharge work, all the discharge earth and sand with more than 300 ton becomes the pile 26c in the discharge site 21. Therefore, it is difficult or may be impossible for an ordinary bulldozer 16 to push out the pile 26c. And even if the bulldoze 16 can push out the pile 26c, such piles 26c are piled up at plural target discharge positions 26′ in the discharge site one after another. And, the amount of discharge work may exceed the capability of leveling work, resulting in decreased work efficiency. Furthermore, to enhance the capability of leveling work, it is necessary to use a larger bulldozer 16, strengthen the pulling power, or increase the number of the bulldozers 16, which may lead to increase in cost of the vehicles.
For this reason, considering only efficiency or cost of the leveling work, it is desirable to employ the related art 1 in which leveling work can be efficiently performed by a bulldozer with ordinary power. As mentioned above, the related art 1, however, requires time or cost for the teaching work on a running course, thus there remains a problem that time or cost required for generating the running course increases.